Turbocharger life on high performance internal combustion engines is commonly limited by fatigue of the compressor or turbine wheel. Turbocharger wheel life is a function of both the maximum turbocharger speed and low cycle fatigue resulting from repetitive cycling the speed of the turbocharger from a high speed to a low speed. U.S. Pat. No. 4,279,576 describes an electromagnetic device for determining the speed of a turbocharger.